ITUNSMPB tag deleted from AAC-files

I use nero AAC (newest version) to encode from FLAC to AAC.

When I display the AAC-file I see an ITUNSMPB extended tag (it's used for gapless playback calculation).

Normally I populate the tags in the encoded files by copying the tags from the FLAC-files and pasting them into the encoded files - but then this tag disappears from the AAC-files.

I'm on v2.49, have been through the settings but can't find any obvious explanation to this.

Existing tag fields are not kept if you use the paste tag command.
You have to save this tag field to a text file or maybe in the file name before you paste the flac tags and import it afterwards.

Or you use a program that copies the tags during the conversion (like foobar2000, ...)

OK, I see - but is an Export/Import an easy process to set up?

How about implementing a feature like Merge Paste, ie overwrite tags which are represented in the paste buffer and leave the rest as they are?
Or better still: this could be the default behaviour for paste - you could still make sure that no old tags survived by deleting all destination tags first, then copy + paste?

EDIT 13. septermber 2011:

A few more questions:

  1. Has Copy/Paste from Edit Menu the exact same functionality as right-click Tag Copy/Tag Paste?

  2. Saw this in the FAQ (Tag Copy):

It seems that the documentation is not accurate - maybe the destructive nature of the paste should be mentioned?
Please also give comment about my feature suggestions?

Regards & thanks for a great program